Two Cultures, or Many?

One of the most pernicious myths in neuroscience is that of the left brain/right brain divide. You have surely heard it before: the idea that half our brain is logical, scientific, and calculating while the other is creative, artistic, and empathic. There is no evidence for such a distinction in the actual brain, but the simplistic categories give people easy ways to identify themselves, and others, as members of tribes with specific values. It’s just as easy to feel good about yourself for supposedly having a brain that’s rational or creative as it is to put someone else down for being too cold or impulsive. This myth isn’t about the brain or neuroscience at all: it’s about putting ourselves, and others, into groups.

false dichotomy

In the pursuit of knowledge, similar false dichotomies can arise. Those seeking to understand science may think of themselves as fundamentally different from those seeking to grasp history or literature, and vice versa. This was most famously written about in C.P. Snow’s Two Cultures essay, where he noted the division and in fact the disdain that had arisen between intellectuals in the humanities and the sciences, and how this prevents people from pooling their knowledge to solve the great problems facing humanity. After all, if you do not respect the source of someone else’s knowledge, why would you bother to listen to them?

We should know better. After all, knowledge isn’t just a dry list of facts, but a set of underlying connections between those facts and ideas, as well as an understanding of context (whether it’s human context or physical context). People who study interdisciplinary fields like nanoscience, my area, know that a chemist can bring a very different approach than a physicist does to the same problem. Often both are useful in gaining understanding. Why not extend this same respect to the social sciences and humanities? And why do we not bat an eyelid when someone says they ‘don’t get’ science, when we’d be appalled if they said they couldn’t read?

In my view, an open mind is critical to any pursuit, whether it’s scientific, literary, or even comedic. Don’t limit yourself by how others think before you; go outside the pre-existing accepted framework to solve problems. Isn’t that true creativity, which is required for any academic pursuit as well as for the simple but rewarding task of making sense of this world? Rather than drawing a line between science and the arts, between types of people, we should share our knowledge and natures, expanding our understanding by sharing our humanity.

world

Hotwiring the Brain

The most complex electrical device we possess isn’t in our pockets, it’s in our heads. Ever since Emil du Bois-Reymond’s discovery of electrical pulses in the brain and Santiago Ramón y Cajal’s realisation that the brain was composed of separate pieces, called neurons, we have known that the brain’s behaviour stems from its independent electrical parts. Many scientists are studying electronic implants that can affect how our brains think and learn. New research on conducting polymers that work well in the body may bring us one step closer to the ability to manually overhaul our own brains.

Ramón y Cajal’s drawings of two types of neurons in 1899.

Ramón y Cajal’s drawings of two types of neurons in 1899.

The immediate brain health implications of plugging electronics into the brain, even with a very basic level of control, would be astounding. The connections in the brain can adapt in response to their environment, forming the basis of learning. This ‘plasticity’ means the brain could adapt in response to implanted electronics, for example by connecting to prosthetic limbs and learning to control them. Implantable electrodes which can excite or inhibit neural signals could also be used for treatments of disorders stemming from bad neural patterns, such as epilepsy and Parkinson’s disease.Since the 1970s, brain-computer interfaces have been studied intensively. Passive electrodes which can record brain waves are already in widespread medical use. Invasive but accurate mapping of brain activity can be done by cutting the skull open, as neurosurgeons do during surgery to avoid tampering with important areas. Less invasive methods like electroencephalography (EEG) are helpful but more sensitive to noise and unable to distinguish different brain regions, not to mention individual neurons. More active interfaces have been built for artificial retinas and cochleas, though the challenge of connecting to the brain consistently and for a long time makes them a very different thing from our natural eyes and ears. But what if we could directly change the way the brain works, with direct electronic stimulation?

However, current neural electrodes made from metal cause problems when left in the brain long term. The body views foreign bodies in the brain as a problem and over time protective cells work to minimize their impact. This immune response not only damages the brain region around the electrode, it actually works to encapsulate the electrode, insulating it electrically from the brain and removing its purpose in being there.

These issues arise because of how hard and unyielding metal is compared to tissue, as well as the defense mechanisms in the body against impurities in metal. Hypoallergenic metals are used to combat this issue in piercings and jewelry, but the brain is yet more sensitive than the skin to invasive metals. A new approach being researched by scientists is the use of conducting polymers to either coat metal electrodes or to even comprise them, removing metal from the picture altogether.

Conducting polymers are plastics, which are more soft and mechanically similar to living tissue than metal. Additionally, they conduct ions (as do neurons in the brain) and are excellent at transducing these to electronic signals, giving high sensitivity to neural activity. Researchers at the École des Mines de Saint-Étienne in France have now demonstrated flexible, implantable electrodes which can be used to directly sense of stimulate brain activity in live rats, without the immune reaction plaguing metal electrodes.

It’s a big step from putting organic electronics in the brain and reading out activity to uploading ourselves to the cloud. But while scientists work on improving resolution in space and time in order to fully map a brain, there is already new hope for those suffering from neurodegenerative diseases, thanks to the plasticity of the brain and the conductivity of plastic.

Science Capital

There are lots of different approaches to understanding who studies science and even who feels entitled to talk about it, but the idea of Science Capital is an especially interesting one.

Science capital comes from not just what you know, but also how you think, what you do, and who you know: the cultural factors that lead someone to feel interested and, perhaps more importantly, accepted in science. Enterprising Science have a nice video about the idea and how they are working to measure it:

For those working in science communication, it’s an important reminder to consider how we can not just pass on knowledge, but help others build up more science capital so that they feel entitled to be part of the conversation.

Sound and Waves

When I hear my mother’s voice, it sounds different from my father’s voice, and different from a bird or a drum. Why are the sounds we hear so varied, and how do they travel to our ears?

soundwaves

Sound is created when something moves rapidly, and creates a wave in the air around it. Our vocal cords do this, as does the skin on a drum, pushing the wave out into the world. This wave is made up of bands of air: more pressure, less pressure, high and low, back and forth as long as the sound lasts. Sound can only travel through something whose pressure can be changed, like air and water. So if you’re floating in space: perfect quiet.

But have you ever noticed how sound changes as it echoes around a gym? That’s because sound waves change when they bounce off things. A musical note will sound differently in a glass room than in one lined with velvet cushions. This affects musical instruments too! And the size of an instrument influences the sound it makes, from the deep growl of the tuba to the light chirp of a flute. Generally, bigger instruments make deeper sounds, with fewer waves per second.

And sound is not just high or low. Of course, it’s also soft or loud. But more interesting are differences that lead to a new tone or feel. For example, a violin and a flute might play the same note at the same volume, but they still won’t sound the same. Waves have amazing abilities to send subtle differences within a sound. And luckily for us, our ears use delicate hairs to detect these waves as they move through the air. Nerves connect the hairs to our brain, connecting us to the full orchestra of sound.

Gravitational Waves Discovered by LIGO

The world is abuzz with news that gravitational waves have been detected for the first time. This is a huge leap forward for scientists’ understanding of gravity! For all that we experience gravity every day as we (mostly) stay grounded on the Earth, figuring out exactly how it works has been a challenge.

Gravity draws things together, but how ? One of the most brilliant discoveries of Albert Einstein was realizing that objects with mass actually warp spacetime itself. If we imagine space as an enormous sheet, throwing a light object like a tennis ball onto it would only pull the sheet down a little, whereas a bowling ball would pull the sheet down significantly more. Everything with mass distorts the sheet though, affecting other objects on the sheet and even massless things like light as they pass through.

Spacetime_curvature

Seeing that gravity affected light was actually the first major proof of Einstein’s theory of general relativity. During an eclipse in 1919, light from a cluster of stars was seen to distort from its normal pattern as it passed close to the temporarily obscured Sun. But another consequence of Einstein’s work was the idea that the speed of light is a maximum speed for any particle or force, including gravitation, however it’s propagated. This implies that gravitational interactions can only happen so fast, and that if a huge gravitational event were to take place emitting a lot of gravitational energy, that energy would have a maximum speed to move through the universe.

What kind of huge gravitational event? Well, the strongest gravitational interactions we have been able to observe take place around black holes, whose mass causes gravitational forces that overcome even basic quantum mechanical ones that prevent matter from piling up on itself. So black holes are supermassive point objects, singularities with exceptionally strong gravity. And if two of them were to come together, their movement might create gravitational waves in spacetime itself that could be strong enough for us to detect.

The Laser Interferometer Gravitational-Wave Observatory (LIGO) has been looking for gravitational waves using light as a ruler to measure whether spacetime is being warped. LIGO compares the length of two 2.5 mile long tunnels, set at right angles to each other, which would warp in alternation if a gravitational wave were to pass through them. The precision needed to see even very strong gravitational waves is tremendous, as we know from the fact that we don’t just observe our living rooms getting bigger and smaller in response to cosmic events. LIGO has been searching for gravitational waves since 1992, and improving its precision since then. Finally this week, they announced a signal!

LIGO_measurement_of_gravitational_waves

The gravitational waves detected come from two black holes merging, a billion light years from our planet. These black holes were enormous, 36 and 29 times the mass of our Sun. They merged into a black hole 62 times the mass of our Sun, converting three solar masses into energy as gravitational waves. It is these waves that the LIGO researchers managed to detect, corroborating their results at two separate facilities in Louisiana and Washington. The difference in lengths of the LIGO tunnels due to the gravitational waves was less than a millionth of the size of an atom, an astounding physical feat, and yet the LIGO collaboration is confident in its measurements to 99.9999%.

Validating a prediction made over a hundred years ago about the way mass warps spacetime is impressive enough, especially considering that gravity is still the least well understood of the four fundamental forces. But it’s also a beautiful new way to look at the stars, and at the massive universe beyond our planetary doorstep.

You Are Here

It’s one of the biggest questions there is: how the universe came to be here, and how we came to be here in it. A beautiful radio documentary, You Are Here, answers these questions on a short walk through Dublin, talking to astrophysicists, geologists, and geneticists to tell us how we came to be where we are. The story is mesmerizing and very well told, and best of all you can listen online:

Color and the Size of Light

What is color, and what does it mean for an object to have a specific color? Well, color comes from the fact that light can have different sizes, the way objects reflect that light, and the way our eyes can see it.

Light is made up of these tiny packets of energy, photons, which travel as waves that can move through air or space. And there’s a distance between the peaks of the waves, the same way there would be for waves in water, which is the size of the light. Light can have a whole range of different sizes, so the microwaves that you use to cook food or the radio waves that carry sound through the air are both different sizes of light. But there’s a special range of light, the visible range, which contains the sizes of light that our eyes can detect.

wavelength_size

So in the visible range, we have shorter lengths of light, which our eyes see as more blue, and longer lengths of light, which our eyes see as more red. In between, you have the full rainbow, which has all the colors we can see. The sun shines light on us with the whole range of sizes, but different objects will reflect different sizes or colors back at us. So an orange is absorbing most visible light but reflecting orange light, and then our eye detects that light and our brain tells us it’s orange.

But we need special cells in our eyes to detect color. Most people have three kinds of color-detecting cells, called cones, that pick up blue, green, or yellow light. From these three colors, our brain puts together the rest of the rainbow, like an artist does when mixing paint. People who have fewer or more kinds of cones will perceive color differently, maybe being color-blind or seeing even more colors than average, even though the light itself is the same!

If you want to know more, we have some nice posts in the archives about visible light and why the sky is blue.